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From:   Joel Fernandes <joel@joelfernandes.org>
Mime-Version: 1.0 (1.0)
Subject: Re: [RFC PATCH 3/4] rculist.h: Fix parentheses around macro pointer parameter use
Date:   Fri, 5 May 2023 10:35:39 -0400
Message-Id: <D4B84962-D9A0-4405-BD07-22E9E2ACA243@joelfernandes.org>
References: <20230505100621.5d468f95@gandalf.local.home>
Cc:     Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        linux-kernel@vger.kernel.org,
        "Paul E. McKenney" <paulmck@kernel.org>,
        Frederic Weisbecker <frederic@kernel.org>,
        Neeraj Upadhyay <quic_neeraju@quicinc.com>,
        Josh Triplett <josh@joshtriplett.org>,
        Boqun Feng <boqun.feng@gmail.com>,
        Lai Jiangshan <jiangshanlai@gmail.com>,
        Zqiang <qiang1.zhang@intel.com>, rcu@vger.kernel.org
In-Reply-To: <20230505100621.5d468f95@gandalf.local.home>
To:     Steven Rostedt <rostedt@goodmis.org>
Precedence: bulk


> On May 5, 2023, at 10:06 AM, Steven Rostedt <rostedt@goodmis.org> wrote:
>=20
> =EF=BB=BFOn Thu, 4 May 2023 12:19:38 -0400
> Joel Fernandes <joel@joelfernandes.org> wrote:
>=20
>>>  void f(void)
>>>  {
>>>          struct test *t1;
>>>          struct test **t2 =3D &t1;
>>>=20
>>>          list_for_each_entry_rcu((*t2), &testlist, node) {       /* work=
s */
>>>                  //...
>>>          }
>>>          list_for_each_entry_rcu(*t2, &testlist, node) { /* broken */
>>>                  //...
>>>          } =20
>>=20
>> Yeah it is not clear why anyone would ever want to use it like this.
>> Why don't they just pass t1 to list_for_each_entry_rcu() ? I would
>> rather it break them and they re-think their code ;).
>=20
> Remember interfaces should not be enforcing policy unless it's key to the
> way the interface works.

Oh yeah, 100% agree. I am not particularly against this particular patch but=
 I also dont see it as solving any problem. Feel free to Ack the patch if yo=
u feel strongly about wanting it.

 - Joel


>=20
> -- Steve